San Diego Regional Data Library » SD Water Quality

In this beachwatch analysis notebook, outputs 19 and 53 suggest that some stations have a reliable seasonal variation in bacteria counts -- a peak in the winter, a low in the summer -- while other look fairly random.

What is the cause of the reliable and unreliable seasonality? Do the stations that don't show a seasonal variation have too few samples to show a seasonal pattern, or is there some other issue? Also try to consider the distance of the stations from storm drains.